science 7

• Troposphere


  The closest layer to the earth's surface, where most weather conditions and phenomena occur, and where most clouds are formed
• Troposphere


  • It is the densest layer of the atmosphere as more dense gases are found here and almost 75% of all the gases constitute this layer
  • The temperature drops by about 6.5°C as the altitude increases by one kilometer from the Earth's surface
  • At the top of the troposphere is the tropopause where there is no observable change in temperature
• Stratosphere


  The layer next to the troposphere, where weather balloons are stationed and the ozone layer is found
• Stratosphere


  • It plays an important role in protecting lifeforms from damaging UV radiation
  • The UV rays are absorbed by the ozone molecules and are transformed into longer wavelengths of radiation that raise the temperature in the stratosphere as the altitude increases
  • The rising temperature brings less turbulence which makes it ideal for a commercial jet
  • The stratosphere is separated from the upper layer through the stratopause
• Mesosphere


  The least studied layer of the atmosphere, where weather balloons and aircraft cannot fly high enough to reach
• Mesosphere


  • It is made of a thin layer of air but enough to burn space debris called meteors
  • It is considered as the coldest layer, with a temperature of about -90°C near the top
  • Very high clouds called the noctilucent clouds form in the mesosphere
  • Lightning-like electrical discharges called sprites and ELVES also appear in the mesosphere
  • The mesopause separates the mesosphere from the next layer
• Thermosphere


  The hottest distinct layer of the atmosphere above the mesosphere
• Thermosphere


  • The temperature in this layer suddenly rises as high-energy X-rays and UV rays from the Sun are directly absorbed by the least dense air molecules, raising its temperature to thousands of degrees
  • Though the temperature is high enough to cause burns, the thermosphere feels cold to our sense of touch due to the thinness of the atmosphere
  • The ionosphere is created in this layer, which plays an important role in radio transmission
  • Auroras are formed in the thermosphere due to the collision of subatomic particles from space with the particles in this region
  • Low-orbiting satellites and the ISS are found here
  • The thermopause separates the thermosphere from the exosphere
• Exosphere


  The uppermost region of the Earth's atmosphere that merges with outer space, with the thinnest atmosphere where the least dense particles simply escape to the void of space
• Exosphere


  • Gases that form the exosphere are directly exposed to the different electromagnetic waves
  • High-orbiting satellites are found in the exosphere
• Air movement


  1. When the air over the land is heated during the day, the air expands and rises and creates a low-pressure area

  2. The air over the water is colder due to the higher heat capacity of the water than the land, creating a high-pressure area

  3. The air moves from the high-pressure area to the low-pressure area, replacing the rising warm air over the land

  4. During the night, the air over the land is colder than the air over the water, and the air moves from the high-pressure area (colder area) towards the low-pressure area (warmer area)
• Sea-breeze


  Occurs during the day when the land heats up faster than the sea
• Land-breeze


  Occurs during the night when the sea is still warm
• Monsoons


  Weather systems that always blow from cold to warm regions or from an area of high pressure to an area of low pressure
• Monsoons


  • The summer monsoon (southwest monsoon or habagat) is associated with heavy rainfall and usually occurs from June to September
  • The winter monsoon (northeast monsoon or amihan) is associated with a cold climate and usually starts in November and ends in February
  • The southwest monsoon comes from the southern part of the Philippines while the northeast monsoon comes from Siberia in Russia
• Intertropical Convergence Zone (ITCZ)


  The region that circles the Earth, near the equator, where the trade winds of the Northern and Southern Hemispheres come together
• Intertropical Convergence Zone (ITCZ)


  • The intense Sun and warm water of the equator heat the air in the ITCZ, raising its humidity and making it buoyant
  • Aided by the convergence of the trade winds, the buoyant air rises, expands and cools, releasing the accumulated moisture in an almost perpetual series of thunderstorms
  • Seasonal shifts in the location of the ITCZ drastically affect rainfall in many equatorial nations, resulting in the wet and dry seasons of the tropics rather than the cold and warm seasons of higher latitudes
  • The longer-term changes in the ITCZ can result in severe droughts or flooding in nearby areas
• Earth's rotation


  The spinning motion of the planet on its axis
• Earth's rotation


  • Observed from the North Pole, the Earth rotates counterclockwise (prograde motion)
  • One whole rotation is equal to 23 hours and 56 minutes, which is one day
• Earth's revolution


  The movement of the Earth along its orbit around the Sun
• One whole travel of the planet around the Sun is equal to 365 and ¼ days
• The Earth's orbit is not a perfect circle but highly eccentric
• Earth's tilted axis of rotation


  The Earth's axis of rotation is tilted by 23.5° from the perpendicular line of its orbital plane
• The Earth's axis points in the same direction throughout the year, currently towards Polaris (the North Star)
• The Earth's tilted axis


  Causes the length of daylight to vary throughout the year

  
• The variation in length of daylight is least observed at the equator and varies greatly in the Polar Regions

  
• Some places experience all daylight the whole day in summer and almost completely dark in winter
• The Earth's tilted axis

  Causes the ecliptic to be tilted by about 23.5° relative to the celestial equator
• The Earth's tilt towards the Sun


  Causes the length of daytime in the Northern Hemisphere to be longer than the length of nighttime during summer
• The Earth's tilt away from the Sun


  Causes the length of daytime in the Northern Hemisphere to be much shorter during winter
• Longer daytime


  Means greater amount of energy received by the Earth's surface
• During summer


  The Sun's path is longer, the Sun is high in the sky, and the Earth's surface receives more exposure to the Sun's rays

  
• During winter


  The Sun's path is shorter, the Sun is low in the sky, and the Earth's surface receives less exposure to the Sun's rays
• The Earth is at its farthest position from the Sun


  During summer, it takes a longer time for the Sun to set
• The Earth is at its nearest position to the Sun


  During winter, the Sun rises late and sets early
• Direct rays


  The ground directly receives the vertical rays of the Sun because the rays hit the ground at a 90° angle

  
• As the season approaches winter


  The angle of the Sun's rays decreases and they hit the ground at an oblique angle because the Sun becomes lower in the sky

  
• The energy received by the Earth's surface depends on the height of the Sun in the sky
• During summer, the Sun is high in the sky


  The energy received by the hemisphere that leans toward the Sun is more concentrated compared to the energy it receives when it tips away from the Sun
• The greater the distance of the Sun in the sky


  The greater the amount of energy received by the hemisphere